It is known in the art to scramble broadcast messages for communication privacy. For example, R. W. Tobias, Jr. in U.S. Pat. No. 4,972,479, Nov. 20, 1990 provides a cellular telephone system with scrambled broadcast messages between mobile units and telephone company cell sites wherein the telephone company descrambles the broadcast communications for wire communication to a called party station thereby avoid descrambling equipment at all of the called party stations. Security is limited because of the several system locations at which descrambling keys are available and because of relatively unsecured communications in the telephone switching system serving the called party. Thus, there is no feasible way to secure many people at many locations so that it is not reasonably possible to intercept private communications. Nor is this system feasible for eliminating the possibility of theft and fraud in two-way systems accommodating interactive purchasing transactions including payment from credit cards, deposits or bank accounts.
In a Satellite Business Communication System set forth by T. Hotta, et al. in U.S. Pat. No. 4,980,677 issued Dec. 25, 1990, a public telephone system links an operator manned central control supervising station and terminal stations coupled in a satellite network. Thus, privacy is not practically securable in a way that prevents fraud by outside parties who may intercept messages or intrude into the system.
In prior subscription television systems, encryption techniques are used for message protection, for example to assure pay for viewing as a condition for descrambling. Such systems are exemplified by U.S. Pat. Nos. to K. S. Gilhousen, et al., 4,613,901, Sep. 23, 1986 for a Signal Encryption and Distribution System; G. O. Crowther, et al., 4,937,866, Jun. 26, 1990 for a System of Decoding Transmitted Scrambled Signals; and T. Kamitake, 4,751,732, Jun. 14, 1988 for a Broadcasting System sending programs to subscribers via satellite. Even though scrambling and access keys are used in these systems, they are all relatively easy to intrude and obtain access by counterfeiting coded cards or otherwise obtaining the decoding key from the broadcast information such as by computer analysis of broadcast signals.
The prior art systems do not provide an acceptable degree of security that communications are protected without the danger of intrusion and fraud. This is particularly so in systems in which purchase transactions are broadcast over a satellite network for purchasing services or goods interactively with incorporated payment transactions, which require access codes to specified bank funds, deposits or credit cards.
Furthermore the prior art interactive purchasing systems process information that may be private, such as subscriber identification numbers and customer lists, without adequate security safeguards against intrusion and fraud. For example, poorly secured customer and vendor identification lists, and private key codes may become accessible for intrusion or fraud.
It is therefore a general objective of this invention to produce a secure interactive satellite broadcast system for protecting privacy.
It is a more specific objective of the invention to produce point-to-point communications broadcast via satellite without identifying messages, participants, transactions, or payment sources.